source-map support for 6to5/register

lib/6to5/register.js

@@ -1,12 +1,25 @@
 require("./polyfill");
 
-var maps = {};
+var sourceMapSupport = require("source-map-support");
-var to5  = require("./index");
+var to5              = require("./index");
-var old  = require.extensions[".js"];
 
-// TODO: source maps - Error.prepareStackTrace override
+sourceMapSupport.install({
+  retrieveSourceMap: function (source) {
+    var map = maps[source];
+    if (map) {
+      return {
+        url: null,
+        map: map
+      };
+    } else {
+      return null;
+    }
+  }
+});
 
 var ignoreRegex = /node_modules/;
+var maps        = {};
+var old         = require.extensions[".js"];
 
 require.extensions[".js"] =
 require.extensions[".es6"] = function (m, filename) {

package.json

@@ -44,7 +44,8 @@
     "recast": "0.8.0",
     "source-map": "0.1.40",
     "regenerator": "0.6.7",
-    "chokidar": "^0.9.0"
+    "chokidar": "^0.9.0",
+    "source-map-support": "^0.2.7"
   },
   "devDependencies": {
     "es6-transpiler": "0.7.17",